This invention relates generally to electrical connectors for connecting coaxial cables and, more particularly, electrical connectors that removably interconnect multi-wire cables.
As electronic products have grown in complexity, it has become necessary to removably connect an increasing number of wires between products and between components within those products. One way of organizing multiwire connections has been to gather the wires into cables. Such cables can gather the wires into either a cylindrical cross-section or a flat ribbon that contains one or more planes or layers of multiple wires extending in a parallel relationship. One such arrangement is described in U.S. Pat. No. 5,084,594 to Cady et al.
As the complexity and density of the wires within cables have increased, the problems associated with removably connecting all of the wires in an easy-to-use, low-cost, and yet reliable manner have increased. The integrity of the electrical connections and insulations must be maintained, which means that the connector must offer secure and positive mating engagement despite small clearances between wires. In addition, the connection cannot be a source of electromagnetic interference or other discontinuity for the signals passing through the wires, and the forces required to connect and disconnect the wires cannot be excessive.
For many modern devices, the cables are comprised of coaxial wires, each wire having an inner or center conductor concentrically surrounded by an insulating sheath and then by an outer conductor, or conductive shield. Often, the coaxial wires are covered with an insulating layer before they are gathered into a cable. Coaxial wires increase interconnection problems because both the center conductor and the outer conductive shield must be terminated. Furthermore, coaxial wires are often used in high-frequency signal applications in which it is important for the electrical connector between two wires being connected to provide the same characteristic impedance as the wires. Electrical signals passing through a coaxial wire develop an electrical field between the center and outer conductors and any loss in continuity of the electrical field results in deterioration of the signal quality. Therefore, it is also important to provide a minimum electrical discontinuity for signals passing along one coaxial wire through the connector to a connected coaxial cable. The continuity must be maintained for all wires in the cable.
Multiple-wire connectors have been developed with reasonably good connection and disconnection forces and with reasonably good electrical connection between conductors. Such connectors, however, tend to be fairly expensive to manufacture and can be difficult to connect to coaxial-wire cables. They also tend to cause undesirably large discontinuities in the electric fields of high frequency signals passing through the cables.
U.S. Pat. No. 3,573,704 to Tarver describes a cable connector that connects a flat ribbon coaxial cable and a round multi-wire coaxial cable. An adapter connected to the flat cable and another adapter connected to the round coaxial cable are connected to a connector block that maintains an impedance match between the two adapters. A non-conductive mounting bar is mated to a conducting block to obtain a sufficient number of contacts with the conductors of the flat cable.
U.S. Pat. No. 4,365,856 to Yaegashi et al. describes an electrical connector for flat ribbon coaxial cables that uses a signal contact coupled to the end of each center conductor and a ground contact coupled to the outer conductive shield of each coaxial wire. One end of the flat ribbon cable is wrapped around a guide block to properly hold the stripped wire ends. The center conductors are then attached to the signal contacts and the outer conductive shields are attached to the ground contact. The signal contacts and the ground contact are attached to the guide block, which is then inserted into a housing to provide simultaneous termination.
U.S. Pat. No. 4,596,432 to Tighe describes a flat ribbon coaxial cable termination connector in which the conductors of a coaxial cable are connected to a housing that is held within a clamp body.
U.S. Pat. No. 4,628,150 to Luc describes a method of joining the outer conductors of coaxial wires by welding a bridging strap between them.
Various arrangements of double-row electrical connectors for multiple-lead ribbon cables are described in U.S. Pat. No. 4,655,515 to Hamsher et al. and U.S. Pat. No. 4,737,117 to Lockard.
Notwithstanding these developments in the area of electrical connectors, there remains a need for a low cost, reliable, easy-to-use cable connector that provides minimum disruption of the electrical fields attendant to high frequency signals passing through the cable. The present invention satisfies this need.